The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.

NEW YORK (

Trefis

) -- Talk about big shoes to fill. Steve Jobs, who is widely recognized as the driving force behind

Apple

's

(AAPL) - Get Report

culture of innovation that took it from near collapse to become an industry leader and one of the most respected brands globally, resigned from his role as CEO. The company's COO Tim Cook will take over his role, which is a natural fit as Cook has filled in for Jobs in the past and had already assumed his responsibilities on his current leave.

We believe that Apple's product roadmap is largely mapped out for the next two to three years and so Steve Jobs' absence won't impact operations in the near term. However, the main challenge for Cook and Apple overall is whether or not it can continue to foster the same culture of innovation and consumer-focused product development that makes Apple what it is today.

We estimate

Apple's stock value at $510, a 40% premium to the current market price. The market's knee-jerk reaction to Jobs' announcement was that Apple's stock dipped by around 5% in after-market trading hours.

Jobs was instrumental in the success of products like Mac, iPod, iPhone and iPad that thwarted competition from

Google

(GOOG) - Get Report

,

Microsoft

(MSFT) - Get Report

and others to become one of the most valued companies in the world. Rising competition from global competitors such as Korea's

Samsung,

which is Apple's biggest competitor in the smartphone segment, will gain from a weaker Apple. The Korean firm's shares rose after Jobs' announcement.

:

The iPhone is the most valuable product for Apple and accounts for more than 50% of Apple's stock value, according to our estimates. Since the iPhone was introduced in 2007, Apple has gained market share in the mobile phone market at a rapid pace. We estimate that Apple's market share of global mobile phones increased from a mere 0.3% in 2007 to an estimated 5% in 2011, and we expect Apple to continue to gain market share in the coming years as well.

While we believe Apple will continue to execute on its iPhone development in the coming years by making newer version and increasing penetration in emerging markets, the next leg of growth is uncertain. Tablets will certainly help and so will new operating systems, but the next "big thing" could be getting customers to embrace iCloud to fully integrate their devices into one ecosystem that is accessible remotely. This means computing, communications, music and overall interactions will be more mobile and will work together seamlessly. This was the spirit of Jobs' most recent keynote address at the Worldwide Developers Conference.

This will be no small feat though certainly since Apple is already headed down that path with the tight integration among its current devices.

While we believe that the visibility of its current operation are good for the next two to three years, Apple will need to continue to innovate, grow and create new products and experiences to maintain its leadership and stay one step ahead of its competition.

What do you think? Let us know how you think Steve Jobs departure will impact Apple.

See our complete analysis

for Apple stock here.

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This commentary comes from an independent investor or market observer as part of TheStreet guest contributor program. The views expressed are those of the author and do not necessarily represent the views of TheStreet or its management.